With a good hit, most people seem to agree that a 9mm or .40 with good defensive ammunition is enough to stop a threat in most cases. Some insist that nothing short of a .357 or .45 ACP should be used as a defensive carry gun.
The .40 S&W is a step up from the .45 ACP.
I am just asking, where do we draw that line? When do we reach a level of lethality and potential damage that we are throwing away either practical carry or controllability? This is all presuming that a good hit was made with any of the above rounds.
Most people do draw the line based on practical carry or controllability. Even with a .40 S&W, many people have trouble when the gun is only 22 oz. The .40 was originally chambered in a 39-ounce semi-automatic S&W 4006. A .357 Magnum or .44 Magnum are typically chambered in revolvers weighing well over 40 ounces to be controllable. More people these days consider twenty-something ounces as the most they'd be willing to carry. They also find 9x19mm the most practical to control in that weight range.
Is a .44 magnum with deer loads too powerful to be desirable as a practical defensive carry pistol? I think that it is. .45 colt monster loads? Is there anyone at all who would walk out the door carrying a redhawk in .454 or .500?
They are not too powerful. They just require, in order for a person to have good control of it, a gun that's too heavy. The FBI has previously published a dismissal of concerns about over-penetration. Because hit rates are so low in actual shootings, the overwhelming concern for collateral damage should be placed on reducing stray bullets rather than the rare bullet that hits its target but overpenetrates. So the presumably excess power of a heavy Magnum is of little concern. But it does require a very heavy gun to deliver it. That is a very practical concern for most people.
There is some skepticism and even results of research that the additional power of a .44 Magnum (for example) does not add any "stopping power" against human targets. Specifically, FBI researchers and their collaborators with ammunition companies like Vista Outdoors (Federal and Speer), have suggested that once sufficient penetration is achieved with expanding bullets, more velocity does not add anything until the bullet exceeds a certain threshold that overcomes the tissue's elasticity and causes remote wounding effects. They've pegged that velocity at 2200 fps. All of this is disputed by others. What is clear is that a bullet would need more than a little bit of power beyond a 9x19mm to make a big difference, and that increase is certainly going to require a more massive gun to control.
Would anyone here go after a 100-200 pound missouri whitetail with a .458 magnum with african game loads? I know that lots of people carry 12 gauge slugs because of game laws, but would anyone choose that 3" magnum slug if they had the opportunity carry a .308?
Yes, I know that there are people who hunt with a 45-70 with monster loads. I think that it's unnecessary to throw a 300 grain JHP at over 2,000 fps when millions of deer have been taken with traditional bottle necked rounds from 30-06 on downward.
The performance on game animals brings about the same questions about "hydrostatic shock" or remote wounding effects on human targets -- but typically with the opposite effect desired. Essentially, a low velocity load employed against game could potentially reduce meat damage. A .375 H&H Magnum has a massive amount of energy for a small target like whitetail. But the heavy bullet is going much slower than a .257 Weatherby, or even a .223 Remington. Either of those 3300+fps cartridges could result in more meat damage than a .375 H&H. It also depends on bullet construction and shot placement.
Sp the big and slow crowd have an argument in their favor based on reduced meat damage. But there are also proponents of big and slow for "man-stopping." The .45 ACP is one cartridge championed by them, but perhaps an even better example would be the .458 Socom. The 5.56x45mm round should have the velocity for all the hydrostatic shocking effect the FBI regards out of reach for handgun rounds. But to increase the AR-15's/M4's percentage of one-shot incapacitations, the .458 Socom was developed where a larger diameter bullet is sent at velocities much slower than what the FBI claims is the threshold for hydrostatic shock. Is it more effective than the 5.56x45mm?
Ultimately, the answer may not matter because people overwhelmingly prefer light guns and light recoil. I don't foresee a large-caliber cartridge with heavy bullets proliferating in either handguns or carbines because it would generate more recoil and mandate heavier guns while reducing the capacity per weight. Cartridges like the 5.7x28 and 5.56x45 may have gone too light for their intended purpose, but I don't predict a shift back to .45 or .50 caliber and 250 grain or heavier bullets.
